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Date: Tue, 6 Oct 2015 02:51:36 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Matthew Wilcox <willy@linux.intel.com>,
 Keith Busch <keith.busch@intel.com>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
 Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>,
 Alexey Kardashevskiy <aik@ozlabs.ru>,
 David Gibson <david@gibson.dropbear.id.au>,
 Christoph Hellwig <hch@infradead.org>,
 linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
 linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/5 v2] dma-mapping: add generic dma_get_page_shift API
Message-ID: <20151006095136.GB14144@infradead.org>
References: <20151002171606.GA41011@linux.vnet.ibm.com>
 <20151002200953.GB40695@linux.vnet.ibm.com>
 <20151002201142.GC40695@linux.vnet.ibm.com>
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Do we need a function here or can we just have a IOMMU_PAGE_SHIFT define
with an #ifndef in common code?

Also not all architectures use dma-mapping-common.h yet, so you either
need to update all of those as well, or just add the #ifndef directly
to linux/dma-mapping.h.